Many electronic devices, such as aircraft flight deck operational equipment including touch screens, receive input from the aircrew. A touch panel offers intuitive inputting for a computer or other data processing devices. It is especially useful in aircraft cockpit devices where other input devices, such as a keyboard and a mouse, are not readily available.
Touch screens are increasingly being used in the cockpit instead of cursor control devices (CCDs), hard knobs and switches, and hardware keyboards. For alphanumeric input using a touch screen, a virtual keyboard is typically displayed, and the user touches the appropriate keys analogous to pushing keys on a real keyboard. However, many of the known screens particularly suited for low end general aviation applications are relatively small, for example, a key width of about 9 millimeters with 2 millimeters spacing therebetween, and the use of a full keyboard makes each key so small that unacceptable accuracy of the touch may occur, especially during turbulence or with the use of gloves by the aircrew. These known touch panels may require the aircrew's attention over an inordinate amount of time, thereby distracting them from performing other flight duties.
There are many types of touch screen sensing technologies, including capacitive, resistive, infrared, and surface acoustic wave. All of these technologies sense touches on a screen. U.S. Pat. No. 6,492,979 discloses the use of a combination of capacitive touch screen and force sensors. U.S. Pat. No. 7,196,694 discloses the use of force sensors at the peripherals of the touch screen to determine the position of a touch. US patent publication 2007/0229464 discloses the use of a capacitive force sensor array overlaying a display to form a touch screen.
World wide air traffic is projected to double every ten to fourteen years, and the International Civil Aviation Organization (ICAO) forecasts world air travel growth of five percent per annum until the year 2020. Such growth may cause degradation in safety and performance and an increase in an already high workload of the flight crew. One negative influence on flight performance has been the ability for the aircrew to input data while paying attention to other matters within and outside of the cockpit. The ability to easily and quickly input data can significantly improve situational awareness of the flight crew resulting in increased flight safety and performance by reducing the flight crew workload.
Accordingly, it is desirable to provide a method for inputting alphanumeric characters, symbols, or menu items from a plurality of such on a small touch screen having keys sufficiently large for accurate selection. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.